This invention relates to devices for determining the pitch of notes generated by musical instruments.
The tuning procedure for any musical instrument generally requires great skill. Ordinarily, one note is tuned to a standard pitch. The other notes are then tuned relative to the first note and relative to each other by ear. This requires that the tuner be capable of discerning accurately specific frequencies such as "A" which has a fundamental frequency of 440 vibrations per second. Accordingly, several devices have been proposed to assist musicians and other persons involved in tuning instruments in locating exact pitches. U.S. Pat. No. 4,399,732 to Rothschild et al discloses a pitch determination device including a transducer which converts a sound into an electrical signal and a frequency translation circuit for translating the frequency of the electrical signal to a predetermined octave range. A plurality of frequency sensitive circuits are connected to detect the frequencies of individual pitches in the predetermined octave band. This device operates quite effectively but the cost of fabrication is prohibitively high. Accordingly, a need has arisen for a device which is low in cost and can accurately determine the pitch of a succession of individual notes.
U.S. Pat. No. 3,788,184 to Zeiser shows a tuning device in which an input signal is converted to a D.C. voltage. The D.C. voltage is then compared with an attenuator having an output representative of 10 millivolts per Hz.
U.S. Pat. No. 3,144,802 to Faber Jr. et al shows a tuning device in which the frequency of a received signal is determined by counting pulses produced by a frequency generator. A visual display is produced of the exact frequency of the received signal.
U.S. Pat. No. 4,481,857 to Havener shows a system for tuning musical instrument in which the exact frequency of a signal is determined and displayed.
U.S. Pat. No. 4,028,985 to Merritt shows a pitch determination system in which the peaks of a received signal are determined and used to drive a period measuring circuit.
U.S. Pat. No. 4,280,387 to Moog discloses a frequency following circuit in which a plurality of signal peaks are detected and used to produce a voltage proportional to the period between successive peaks.